BEIRUT — Clashes between members of al-Qaida's branch in Syria and a rebel faction in the country's north believed to have been trained by the U.S. government have stopped after the rebels left their headquarters, activists said Saturday.

The fighting came a few days after the U.S. and Turkey announced the outlines of a deal to help rebels push the Islamic State group back from a strip of territory it controls along the Syrian-Turkish border, replacing it with more moderate rebels backed by Washington and Ankara.

Rami Abdurrahman, who heads the Britain-based Syrian Observatory for Human Rights, said members of the Division 30 faction fled to a nearby area controlled by a Syrian Kurdish militia. Abu al-Hassan Marea, a Syrian activist who is currently in Turkey near the Syrian border, confirmed Saturday that Division 30 fighters have withdrawn from their headquarters.

Abdurrahman and Marea said Division 30 had less than 60 fighters and that on Friday alone the group lost five fighters and 18 others were wounded.

A representative of Division 30 did not respond to written questions sent to the group's Facebook account.

Friday's fighting concentrated around the Division 30 headquarters near the northern Syrian town of Azaz. The fighting came days after the Nusra Front detained several members of Division 30, including its commander Col. Nadim al-Hassan.

On Friday night the Nusra Front said it attacked Division 30 and abducted some of its members because they were trained by the CIA and vowed in a statement to cut off "the arms" of the American government in Syria.

A U.S. military official seemed to deny any American connection to Division 30, saying on Friday that no member of a U.S.-backed rebel faction had been abducted.

Also Saturday, Syria's state media and the main Kurdish militia in the country said government forces and Kurdish fighters have captured the last pocket that was held by the Islamic State group five weeks after the extremists stormed the city and captured several southern neighborhoods.

"Out units were able to fully liberate the city of Hassakeh from Daesh's mercenaries and were able to evict them from the city," said a statement from the Kurdish People's Protection Units, or YPG, using an Arabic acronym of the Islamic State group.

Syria's state news agency said Syrian troops "have wiped out that last den of Daesh's terrorists" in Hassakeh.

Hassakeh had been controlled by Syrian troops and Kurdish militia until IS fighters stormed the city in late June.

The YPG has been the main force fighting against IS in Syria under the cover of airstrikes by the U.S.-led coalition.

In central Syria, troops captured several areas and a power station they lost last year in battles with militants including Nusra Front fighters, according to the Observatory and state media. The Observatory said 27 insurgents have been killed since Friday.

Syria's civil war, now in its fifth year, has killed more than 220,000 people and wounded more than a million.